Electrode assemblies for biomedical electrode units use snap fasteners commonly used on clothing or variations of such fasteners, which are relatively complex, expensive, and difficult to assemble. Since they are made as clothing fasteners they are not ideally suited for use as electrodes. When these and other fasteners are mounted on the adhesive pad which adheres to the skin, the lower and upper electrodes may either squeeze the pad too much and distort it or grip it too loosely so that the electrode can wobble relative to the pad and is not held tightly in contact with the skin. In addition, the upper and lower parts of some fasteners may not always seat tightly together; they can wiggle relative to each other and the pad between them. This instability can result in poor or intermittent contact and result in poor electrical continuity between the upper and lower electrodes. In many constructions the base electrode, which carries a sponge disc impregnated with conductive gel for electrical interface with the skin, is hollow so that the gel can move through it to the junction of the electrodes where it can interfere with and cause corrosion of the parts.